JP7462243B2 - Composite Materials - Google Patents

Description

The present invention relates to a composite component.

Conventionally, composite members in which ceramic and plastic are bonded together with an adhesive have been known. However, even if a liquid adhesive is applied to the ceramic or plastic, and then a certain pressure is applied to bond the ceramic and plastic together with the adhesive, it is difficult to obtain sufficient bonding strength.

Therefore, Patent Document 1 discloses a method in which a liquid adhesive is solidified on the surface of a ceramic to form an adhesive layer, and then molten resin is injected onto the ceramic whose surface is covered with the adhesive layer. This method produces a composite in which an adhesive layer is interposed between the ceramic and plastic.

JP 2014-128975 A

In conventional technology, liquid adhesives whose main components are polyvinyl acetate, polyvinyl alcohol, polybutylene terephthalate, dibutyl acetate, and organic solvents are used as adhesives. However, even when such adhesives are used, there is a risk that the ceramic and plastic may peel off if the adhesive layer deteriorates.

The present invention has been made in consideration of the problems inherent in the prior art. The object of the present invention is to provide a composite member in which an inorganic layer and a resin layer are firmly bonded together without the use of an adhesive.

In order to solve the above problems, a composite member according to an embodiment of the present invention comprises an inorganic layer containing an inorganic substance containing at least one of a metal oxide and a metal oxide hydroxide. The composite member comprises a resin layer provided on the surface of the inorganic layer and containing a resin and inorganic particles dispersed in the resin and directly bonded to the inorganic substance of the inorganic layer. The porosity in a cross section of the inorganic layer is 20% or less, and when measured by infrared spectroscopy or X-ray diffraction, a peak derived from a hydroxyl group is detected from the inorganic layer.

FIG. 1 is a schematic diagram illustrating an example of a composite member according to the present embodiment. FIG. 2 is a cross-sectional view that illustrates an example of the inorganic layer according to this embodiment. FIG. 3 is a cross-sectional view showing how the inorganic substance of the inorganic layer and the inorganic particles of the resin layer are directly bonded to each other. FIG. 4 is a cross-sectional view showing how the inorganic material of the inorganic layer and the inorganic particles of the resin layer are continuously and integrally bonded together. FIG. 5 is an SEM image of the test sample of Example 1 observed at 500x magnification. FIG. 6 is an SEM image of the test sample of Example 1 observed at 5000 times. FIG. 7 is an SEM image of the test sample of Example 2 observed at 500x magnification. FIG. 8 is an SEM image of the test sample of Example 2 observed at 5000 times. FIG. 9 is an SEM image of the test sample of Comparative Example 1 observed at 500x magnification. FIG. 10 is an SEM image of the test sample of Comparative Example 1 observed at 5000 times. FIG. 11 is a diagram showing a backscattered electron image at position 1 in test sample 1 of Example 1. FIG. 12 is a binarized image of a backscattered electron image at position 1 in test sample 1 of Example 1. FIG. 13 is a diagram showing a backscattered electron image at position 2 in test sample 1 of Example 1. FIG. 14 is a binarized image of a backscattered electron image at position 2 in test sample 1 of Example 1. FIG. 15 is a diagram showing a backscattered electron image at position 3 in test sample 1 of Example 1. FIG. 16 is a binarized image of a backscattered electron image at position 3 in test sample 1 of Example 1. FIG. 17 shows infrared absorption spectra of the inorganic layer, alumina, and aluminum hydroxide of Example 1. FIG. 18 is a graph showing the XRD pattern of the inorganic layer and the XRD pattern of alumina in Example 1. FIG. 19 is a graph showing an enlarged view of the XRD pattern of FIG. FIG. 20 is a graph showing the fitting results of the XRD pattern of Example 1, and the XRD patterns of boehmite, γ-alumina, and α-alumina registered in the ICSD (Inorganic Crystal Structure Database). FIG. 21 is a graph showing the fitting results of the XRD pattern of alumina, and the XRD patterns of α-alumina and boehmite registered in the ICSD. FIG. 22 is a TG curve of boehmite and aluminum hydroxide.

The composite member and the manufacturing method of the composite member according to this embodiment will be described in detail below with reference to the drawings. Note that the dimensional ratios in the drawings have been exaggerated for the convenience of explanation and may differ from the actual ratios.

[Composite material]
As shown in Fig. 1, the composite material 1 of the present embodiment includes an inorganic layer 10 and a resin layer 20. The resin layer 20 is provided on the surface of the inorganic layer 10. The resin layer 20 may be provided on only one surface of the inorganic layer 10, or on both surfaces of the inorganic layer 10.

(Inorganic layer 10)
The inorganic layer 10 according to this embodiment may include a plurality of particles 11, for example, as shown in Fig. 2. The inorganic layer 10 may be formed by bonding the particles 11 of an inorganic substance to each other.

The inorganic layer 10 may include bonding portions 12 that bond each of the multiple particles 11 together. The inorganic layer 10 may have a portion where the multiple particles 11 bond directly to each other without the bonding portions 12. The bonding portions 12 may cover a portion or the entire surface of each of the multiple particles 11.

The inorganic layer 10 contains an inorganic substance. The inorganic substance may be contained in at least one of the plurality of particles 11 and the bonding portions 12. That is, the inorganic substance may be contained in either the plurality of particles 11 or the bonding portions 12, or may be contained in both the plurality of particles 11 and the bonding portions 12.

The inorganic material contained in the inorganic layer 10 contains at least one of a metal oxide and a metal oxide hydroxide. That is, the inorganic material may contain either a metal oxide or a metal oxide hydroxide, or may contain both a metal oxide and a metal oxide hydroxide. The metal oxide is preferably a compound in which only oxygen is bonded to a metal element.

At least one of the metal oxide and the metal hydroxide oxide preferably contains at least one metal element selected from the group consisting of alkali metals, alkaline earth metals, transition metals, base metals, and metalloids. In this specification, the alkaline earth metals include calcium, strontium, barium, and radium, as well as beryllium and magnesium. The base metals include aluminum, zinc, gallium, cadmium, indium, tin, mercury, thallium, lead, bismuth, and polonium. The metalloids include boron, silicon, germanium, arsenic, antimony, and tellurium. Among these, it is preferable that the inorganic substance contains at least one metal element selected from the group consisting of zinc, aluminum, and magnesium. The inorganic substance containing these metal elements can easily form the bond 12 derived from the inorganic substance by a pressurized and heated method, as described below.

The metal oxide may include at least one selected from the group consisting of zinc oxide, magnesium oxide, and a complex of zinc oxide and magnesium oxide. By using such a metal oxide, it is possible to obtain an inorganic layer 10 having high durability.

The metal oxide hydroxide may include, for example, aluminum oxide hydroxide. An example of an aluminum oxide hydroxide is boehmite, which has the composition formula AlOOH. Boehmite is insoluble in water and hardly reacts with acids or alkalis at room temperature, and therefore has high chemical stability. Furthermore, boehmite has a high dehydration temperature of about 500°C, and therefore has the property of excellent heat resistance. In addition, since boehmite has a specific gravity of about 3.07, when the inorganic layer 10 contains boehmite, it is possible to obtain an inorganic layer 10 that is lightweight and has excellent chemical stability.

When the inorganic substance contained in the inorganic layer 10 is boehmite, the particles 11 may be particles containing only a boehmite phase, or may be particles containing a mixed phase of boehmite and aluminum oxide or aluminum hydroxide other than boehmite. For example, the particles 11 may be particles containing a phase containing boehmite and a phase containing gibbsite (Al(OH) ₃ ) mixed together. Adjacent particles 11 are preferably bonded together via at least one of an aluminum oxide and an aluminum hydroxide. That is, the particles 11 are preferably not bonded together with an organic binder containing an organic compound, and are preferably not bonded together with an inorganic binder containing an inorganic substance other than an aluminum oxide and an aluminum hydroxide. In addition, when adjacent particles 11 are bonded together with at least one of an aluminum oxide and an aluminum hydroxide, the aluminum oxide and the aluminum hydroxide may be crystalline or amorphous.

When the inorganic layer 10 contains boehmite, the proportion of the boehmite phase is preferably 50% by mass or more, more preferably 60% by mass or more, and even more preferably 70% by mass or more. By increasing the proportion of the boehmite phase, it is possible to obtain an inorganic layer 10 that is lightweight and has excellent chemical stability and heat resistance. The proportion of the boehmite phase in the inorganic layer 10 can be determined by measuring the X-ray diffraction pattern of the inorganic layer 10 by X-ray diffraction method and then performing Rietveld analysis.

When the inorganic substance contained in the inorganic layer 10 is boehmite, the bonding portion 12 may contain a boehmite phase. When the bonding portion 12 contains a boehmite phase, the plurality of particles 11 may contain aluminum nitride. Aluminum nitride has a characteristic of high electrical resistance and high dielectric strength, and further exhibits a very high thermal conductivity as a ceramic material. The plurality of particles 11 may not be bonded with an organic binder containing an organic compound, and may not be bonded with an inorganic binder other than the boehmite phase. In addition, as described below, the inorganic layer 10 can be formed by heating a mixture of powder of an inorganic substance and water while pressurizing it, and there is no need to use a reaction accelerator or the like. Therefore, since the inorganic layer 10 does not contain impurities derived from the organic binder, the inorganic binder, and the reaction accelerator, it is possible to maintain the original properties of aluminum nitride and boehmite.

It is more preferable that the inorganic substance contains at least one of the oxide and hydroxide oxide of the above metal element as a main component. That is, it is preferable that the inorganic substance contains at least one of the oxide and hydroxide oxide of the above metal element in an amount of 50 mol% or more, and more preferably in an amount of 80 mol% or more. It is also preferable that the inorganic layer 10 contains at least one of the oxide and hydroxide oxide as a main component. That is, it is preferable that the inorganic layer 10 contains at least one of the oxide and hydroxide oxide in an amount of 50 mol% or more, and more preferably in an amount of 80 mol% or more.

The inorganic substance contained in the inorganic layer 10 is preferably polycrystalline. By using a polycrystalline inorganic substance contained in the inorganic layer 10, it is possible to obtain an inorganic layer 10 having high durability compared to when the inorganic substance is amorphous. The inorganic substance particles 11 may be crystalline particles, and the inorganic layer 10 may be formed by agglomeration of a large number of particles 11. It is more preferable that the inorganic substance particles 11 are crystalline particles containing at least one metal element selected from the group consisting of alkali metals, alkaline earth metals, transition metals, base metals, and semimetals. It is also preferable that the inorganic substance particles 11 are crystalline particles containing at least one of the oxides and hydroxide oxides of the above metal elements. It is more preferable that the inorganic substance particles 11 are crystalline particles containing at least one of the oxides and hydroxide oxides of the above metal elements as a main component.

The inorganic substance contained in the inorganic layer 10 preferably does not contain a hydrate of a calcium compound. The calcium compounds referred to here are tricalcium silicate (alite, 3CaO.SiO ₂ ), dicalcium silicate (belite, 2CaO.SiO ₂ ), calcium aluminate ( _{3CaO.Al 2} O ₃ ), calcium aluminoferrite (4CaO.Al ₂ O 3.Fe ₂ O ₃ ), and calcium sulfate (CaSO _{4.2H 2} O). When the inorganic substance contained in the inorganic layer 10 contains a hydrate of the calcium compound, the porosity of the cross section of the inorganic layer 10 may exceed 20%, resulting in a decrease in strength. Therefore, it is preferable that the inorganic substance does not contain a hydrate of the calcium compound. In addition, it is preferable that the inorganic substance contained in the inorganic layer 10 does not contain phosphate cement, zinc phosphate cement, or calcium phosphate cement. When the inorganic substance does not contain these cements, the porosity of the cross section of the inorganic layer 10 decreases, thereby increasing the mechanical strength.

The average particle diameter of the plurality of particles 11 is not particularly limited. The average particle diameter of the particles 11 is preferably 300 nm or more and 50 μm or less, more preferably 300 nm or more and 30 μm or less, and even more preferably 300 nm or more and 20 μm or less. When the average particle diameter of the inorganic particles 11 is within this range, the particles 11 are firmly bonded to each other, and the strength of the inorganic layer 10 can be increased. In this specification, the value of "average particle diameter" is, unless otherwise specified, a value calculated as the average particle diameter of particles observed in several to several tens of fields of view using an observation means such as a scanning electron microscope (SEM) or a transmission electron microscope (TEM).

The shape of the inorganic particle 11 is not particularly limited, but can be, for example, spherical. The particle 11 may also be a whisker-like (needle-like) particle or a scale-like particle. Compared to spherical particles, whisker-like particles or scale-like particles have a higher contact with other particles, and the strength of the inorganic layer 10 is more likely to be improved. Therefore, by using particles of such a shape as the particle 11, it is possible to increase the strength of the inorganic layer 10 as a whole.

Here, it is preferable that the inorganic substance contained in the inorganic layer 10 does not substantially contain hydrates. In this specification, "the inorganic substance does not substantially contain hydrates" means that hydrates have not been intentionally included in the inorganic substance. Therefore, when hydrates are mixed into the inorganic substance as unavoidable impurities, the condition "the inorganic substance does not substantially contain hydrates" is met. Note that boehmite is a metal oxide hydroxide, and is therefore not included in the hydrates in this specification.

It is preferable that the inorganic layer 10 is composed of a group of particles of an inorganic substance. That is, it is preferable that the inorganic layer 10 is composed of a plurality of particles 11 containing an inorganic substance, and the inorganic layer 10 is formed by bonding the particles 11 of the inorganic substance to each other. In this case, the particles 11 may be in a state of point contact with each other, or may be in a state of surface contact in which the particle surfaces of the particles 11 are in contact with each other.

It is preferable that the bonding portion 12 contains an amorphous inorganic compound. Specifically, the bonding portion 12 may be a portion containing only an amorphous inorganic compound, or a portion containing a mixture of an amorphous inorganic compound and a crystalline inorganic compound. The bonding portion 12 may also be a portion in which a crystalline inorganic compound is dispersed inside an amorphous inorganic compound. When an amorphous inorganic compound and a crystalline inorganic compound are mixed, the amorphous inorganic compound and the crystalline inorganic compound may have the same chemical composition, or may have different chemical compositions.

It is preferable that the inorganic particle 11 and the bond 12 contain the same metal element, and the metal element is at least one selected from the group consisting of alkali metals, alkaline earth metals, transition metals, base metals, and semimetals. That is, it is preferable that the inorganic substance contained in the particle 11 and the amorphous inorganic substance contained in the bond 12 contain at least the same metal element. The inorganic substance contained in the particle 11 and the amorphous inorganic substance contained in the bond 12 may have the same chemical composition or different chemical compositions. Specifically, when the metal element is zinc, the inorganic substance contained in the particle 11 and the amorphous inorganic substance contained in the bond 12 may both be zinc oxide (ZnO). Alternatively, the inorganic substance contained in the particle 11 is ZnO, but the amorphous inorganic substance contained in the bond 12 may be a zinc-containing oxide other than ZnO.

The metal oxide contained in both the particle 11 and the bonding portion 12 is preferably at least one selected from the group consisting of zinc oxide, magnesium oxide, and a complex of zinc oxide and magnesium oxide. As described later, by using these metal oxides, it is possible to form the bonding portion 12 by a simple method.

The porosity in the cross section of the inorganic layer 10 is 20% or less. That is, when the cross section of the inorganic layer 10 is observed, the average ratio of pores per unit area is 20% or less. When the porosity is 20% or less, the occurrence of cracks in the inorganic layer 10 starting from the pores is suppressed, so that the bending strength of the composite material 1 can be increased. In addition, the porosity in the cross section of the inorganic layer 10 is preferably 15% or less, more preferably 10% or less, and even more preferably 5% or less. The smaller the porosity in the cross section of the inorganic layer 10, the more cracks starting from the pores are suppressed, so that the strength of the composite material 1 can be increased.

In this specification, the porosity can be determined as follows. First, the cross section of the inorganic layer 10 is observed to distinguish between pores and non-pores. Then, the unit area and the area of the pores in the unit area are measured to determine the ratio of pores per unit area. After determining the ratio of pores per unit area in multiple locations, the average ratio of pores per unit area is taken as the porosity. When observing the cross section of the inorganic layer 10, an optical microscope, a scanning electron microscope (SEM), or a transmission electron microscope (TEM) can be used. The unit area and the area of the pores in the unit area may also be measured by binarizing an image observed with a microscope.

The size of the pores present inside the inorganic layer 10 is not particularly limited, but it is preferable that they are as small as possible. The small size of the pores suppresses cracks originating from the pores, thereby increasing the strength of the inorganic layer 10 and improving the machinability of the inorganic layer 10. The size of the pores in the inorganic layer 10 is preferably 5 μm or less, more preferably 1 μm or less, and even more preferably 100 nm or less. The size of the pores present inside the inorganic layer 10 can be determined by observing the cross section of the inorganic layer 10 with a microscope, similar to the above-mentioned porosity.

In the composite member 1, when the composite member 1 is measured by infrared spectroscopy or X-ray diffraction, a peak derived from a hydroxyl group is detected from the inorganic layer 10. Specifically, when the peak area of the peak is larger than the background level, it can be determined that the peak is detected from the inorganic layer 10. The peak area depends on the type of material constituting the inorganic layer 10, but can be calculated by a method implemented in the examples described below. When the composite member 1 is measured by infrared spectroscopy, the peak area may be 2 cm ^-1 or more, or 3 cm ^-1 or more. When the composite member 1 is measured by X-ray diffraction, the peak area may be 1000° (2θ)·cps or more, 2000 (2θ)·cps or more, or 4000° (2θ)·cps or more.

When the inorganic layer 10 is heated at a high temperature, the hydroxyl groups are eliminated, so in order to detect the above-mentioned peaks in the inorganic layer 10, it is necessary to heat the inorganic layer 10 at a low temperature. As described below, the inorganic layer 10 can be obtained by applying pressure while heating the raw material at a low temperature, such as 50 to 300°C, so that a peak derived from the hydroxyl groups is detected. In addition, since the inorganic layer 10 can be obtained by applying pressure while heating at a low temperature, for example, a material with low heat resistance can be added to the inorganic layer 10. For example, organic substances such as resin particles and pigments can be added to the inorganic layer 10.

The thickness t1 of the inorganic layer 10 is not particularly limited, but can be, for example, 50 μm or more. The composite member 1 of this embodiment is formed by a pressurized heating method, as described below. Therefore, an inorganic layer 10 with a large thickness can be easily obtained. The thickness t1 of the inorganic layer 10 can be 1 mm or more, and can also be 1 cm or more. The upper limit of the thickness t1 of the inorganic layer 10 is not particularly limited, but can be, for example, 50 cm.

(Resin layer 20)
1 , the resin layer 20 contains a resin 21 and inorganic particles 22. The inorganic particles 22 are dispersed in the resin 21. Thus, the resin 21 covers at least a portion of the surface of the inorganic particles 22. The resin 21 may cover only a portion of the surface of the inorganic particles 22, or may cover the entire surface of the inorganic particles 22.

As shown in FIG. 3, the inorganic particles 22 are directly bonded to the inorganic substance of the inorganic layer 10. By directly bonding the inorganic particles 22 to the inorganic substance of the inorganic layer 10, the adhesive strength between the inorganic layer 10 and the resin layer 20 is improved, so that peeling between the inorganic layer 10 and the resin layer 20 can be suppressed. Note that the adhesion in this embodiment means that the inorganic particles 22 and the inorganic layer 10 are in contact with each other, and the inorganic particles 22 contribute to improving the adhesive strength between the inorganic layer 10 and the resin layer 20. Therefore, the adhesion in this embodiment also includes a case where the inorganic particles 22 and the inorganic layer 10 are in contact with each other, but the inorganic particles 22 and the inorganic substance contained in the inorganic layer 10 are not continuously and integrally bonded.

As shown in Figure 4, it is preferable that the inorganic particles 22 and the inorganic substance contained in the inorganic layer 10 are continuously and integrally bonded. By bonding the inorganic particles 22 and the inorganic substance contained in the inorganic layer 10 in this manner, the inorganic layer 10 and the resin layer 20 are firmly bonded via the inorganic substance and the inorganic particles 22. Therefore, the adhesive strength between the inorganic layer 10 and the resin layer 20 is improved, and peeling between the inorganic layer 10 and the resin layer 20 can be further suppressed.

Resin 21 may be a thermosetting resin or a thermoplastic resin. The thermoplastic resin preferably includes at least one resin selected from the group consisting of polyacrylate, ethylene-vinyl acetate copolymer, olefin resin, polyvinyl butyral, polyethylene terephthalate, and polyimide. The thermosetting resin preferably includes at least one resin selected from the group consisting of polyacrylate, epoxy resin, polyurethane, and polyimide.

The inorganic particles 22 contain, for example, an inorganic substance. The inorganic substance contained in the inorganic particles 22 may contain at least one of a metal oxide and a metal oxide hydroxide. That is, the inorganic substance may contain either a metal oxide or a metal oxide hydroxide, or may contain both a metal oxide and a metal oxide hydroxide. The metal oxide is preferably a compound in which only oxygen is bonded to a metal element. At least one of the metal oxide and the metal oxide hydroxide preferably contains at least one metal element selected from the group consisting of alkali metals, alkaline earth metals, transition metals, base metals, and semimetals.

It is preferable that the inorganic particles 22 contain a metal element contained in the inorganic substance of the inorganic layer 10. When the inorganic substance contained in the inorganic layer 10 and the inorganic particles 22 contained in the resin layer 20 contain the same type of metal element, the reactivity between the inorganic substance of the inorganic layer 10 and the inorganic particles 22 is increased. Therefore, the bond between the inorganic substance of the inorganic layer 10 and the inorganic particles 22 is strengthened, and the adhesion between the inorganic layer 10 and the resin layer 20 can be further improved. The inorganic substance of the inorganic layer 10 and the inorganic substance contained in the inorganic particles 22 may have the same chemical composition or may have different chemical compositions. Specifically, when the metal element is zinc, the inorganic substance of the inorganic layer 10 and the inorganic substance contained in the inorganic particles 22 may both be zinc oxide (ZnO). Alternatively, the inorganic substance of the inorganic layer 10 is ZnO, but the inorganic substance contained in the inorganic particles 22 may be a zinc-containing oxide other than ZnO.

It is preferable that the inorganic particles 22 have a hydroxyl group. The inorganic particles 22 may contain, for example, oxides such as silica and alumina, or hydroxides such as aluminum hydroxide. When the inorganic particles 22 have a hydroxyl group, the inorganic particles 22 and the inorganic material of the inorganic layer 10 are firmly bonded by hydrogen bonds. Therefore, the adhesion between the inorganic layer 10 and the resin layer 20 can be further improved. Whether the inorganic particles 22 have a hydroxyl group can be measured by infrared spectroscopy or X-ray diffraction, as described above.

The average particle diameter of the inorganic particles 22 is not particularly limited. The average particle diameter of the inorganic particles 22 is preferably 300 nm or more and 50 μm or less, more preferably 300 nm or more and 30 μm or less, and even more preferably 300 nm or more and 20 μm or less. By having the average particle diameter of the inorganic particles 22 within this range, the adhesive strength between the inorganic layer 10 and the resin layer 20 can be increased without significantly impairing the mechanical strength of the resin layer 20.

The shape of each of the inorganic particles 22 is not particularly limited, but may be, for example, spherical. In addition, each of the inorganic particles 22 may be a whisker-like (needle-like) particle or a scale-like particle.

The content of inorganic particles 22 in the resin layer 20 is preferably 10% by volume or more and 70% by volume or less. When the content of inorganic particles 22 is 10% by volume or more, the adhesion area between the inorganic substance contained in the inorganic layer 10 and the inorganic particles 22 contained in the resin layer 20 becomes large, so that the adhesion between the inorganic layer 10 and the resin layer 20 becomes high. Also, when the content of inorganic particles 22 is 70% by volume or less, the proportion of resin 21 in the resin layer 20 increases, and a composite member 1 that maintains the characteristics of the resin 21 can be formed. The content of inorganic particles 22 is more preferably 15% by volume or more, and even more preferably 20% by volume or more. Also, the content of inorganic particles 22 is more preferably 50% by volume or less, and even more preferably 30% by volume or less.

The thickness t2 of the resin layer 20 is not particularly limited, but may be, for example, 50 μm or more. The thickness t2 of the composite material 1 may be 1 mm or more, and may also be 1 cm or more. The upper limit of the thickness t2 of the composite material 1 is not particularly limited, but may be, for example, 50 cm.

The shape of the composite member 1 is not particularly limited, but can be, for example, plate-like or film-like. The thickness t3 of the composite member 1 is not particularly limited, but can be, for example, 50 μm or more. The composite member 1 of this embodiment is formed by a pressurized heating method, as described below. Therefore, a thick composite member 1 can be easily obtained. The thickness t3 of the composite member 1 can be 1 mm or more, and can also be 1 cm or more. The upper limit of the thickness t3 of the composite member 1 is not particularly limited, but can be, for example, 50 cm.

Thus, the composite member 1 of this embodiment comprises an inorganic layer 10 containing an inorganic substance containing at least one of a metal oxide and a metal oxide hydroxide. The composite member 1 comprises a resin layer 20 provided on the surface of the inorganic layer 10, which contains a resin 21 and inorganic particles 22 dispersed within the resin 21 and directly bonded to the inorganic substance of the inorganic layer 10. The porosity of the cross section of the inorganic layer 10 is 20% or less, and when measured by infrared spectroscopy or X-ray diffraction, a peak derived from a hydroxyl group is detected from the inorganic layer 10.

In the composite member 1 according to this embodiment, the inorganic particles 22 of the resin layer 20 are directly bonded to the inorganic material of the inorganic layer 10. Therefore, in the composite member 1, the inorganic layer 10 and the resin layer 20 are firmly bonded without the use of an adhesive. In addition, the porosity in the cross section of the inorganic layer 10 is 20% or less, and the occurrence of cracks in the inorganic layer 10 starting from the pores is suppressed, so that the bending strength of the composite member 1 can be increased. Furthermore, since the inorganic layer 10 can be obtained by applying pressure while heating at a low temperature as described below, for example, a member with low heat resistance can be added to the inorganic layer 10.

[Method of manufacturing composite member]
Next, a method for manufacturing the composite material 1 according to this embodiment will be described.

First, a method for producing the composite member 1 in which the inorganic substance contained in the inorganic layer 10 is boehmite will be described. The composite member 1 in which the inorganic substance is boehmite can be produced by mixing hydraulic alumina with a solvent containing water, and then pressurizing and heating the mixture. Hydraulic alumina is an oxide obtained by heat-treating aluminum hydroxide, and contains ρ-alumina. Such hydraulic alumina has the property of bonding and hardening through a hydration reaction. Therefore, by using a pressurized heating method, the hydration reaction of hydraulic alumina progresses, and the hydraulic alumina bonds to each other, while the crystal structure changes to boehmite, thereby forming the inorganic layer 10.

Specifically, first, hydraulic alumina powder is mixed with a water-containing solvent to prepare a mixture. The water-containing solvent is preferably pure water or ion-exchanged water. The water-containing solvent may contain an acidic or alkaline substance in addition to water. Furthermore, the water-containing solvent may contain water as the main component, and may contain, for example, an organic solvent (such as alcohol).

The amount of solvent added to the hydraulic alumina is preferably an amount that allows the hydration reaction of the hydraulic alumina to proceed sufficiently. The amount of solvent added is preferably 20 to 200% by mass, more preferably 50 to 150% by mass, relative to the hydraulic alumina.

Next, a resin layer containing resin and inorganic particles is placed inside the mold. Then, the mixture obtained by mixing hydraulic alumina and a solvent containing water is filled inside the mold so that the mixture is placed on the surface of the resin layer. After the mixture is filled into the mold, the mold may be heated as necessary. Then, pressure is applied to the resin layer and the mixture placed inside the mold, and the inside of the mold is put into a high-pressure state. At this time, the hydraulic alumina is highly filled, and the hydraulic alumina particles are bonded to each other, thereby increasing the density. Specifically, by adding water to the hydraulic alumina, the hydraulic alumina undergoes a hydration reaction, and boehmite and aluminum hydroxide are generated on the surface of the hydraulic alumina particles. Then, by applying pressure to the mixture while heating it inside the mold, the generated boehmite and aluminum hydroxide diffuse between adjacent hydraulic alumina particles, and the hydraulic alumina particles are gradually bonded to each other. Thereafter, a dehydration reaction proceeds due to heating, and the crystal structure changes from aluminum hydroxide to boehmite. It is assumed that the hydration reaction of hydraulic alumina, the mutual diffusion between hydraulic alumina particles, and the dehydration reaction proceed almost simultaneously. In addition, by applying pressure to the mixture and the resin layer while heating, the inorganic substance derived from the mixture is directly fixed to the inorganic particles of the resin layer. For example, the hydraulic alumina particles are directly fixed to the inorganic particles of the resin layer.

Then, by removing the molded body from inside the mold, a composite material 1 having an inorganic layer 10 and a resin layer 20 can be obtained.

The heating and pressurizing conditions for the mixture of hydraulic alumina and a solvent containing water are not particularly limited as long as the reaction between hydraulic alumina and the solvent proceeds. For example, it is preferable to heat the mixture of hydraulic alumina and a solvent containing water to 50 to 300°C and pressurize it at a pressure of 10 to 600 MPa. The temperature at which the mixture of hydraulic alumina and a solvent containing water is heated is more preferably 80 to 250°C, and even more preferably 100 to 200°C. When the resin contained in the resin layer is a thermoplastic resin, it is preferable to heat it at a temperature equal to or lower than the melting point of the thermoplastic resin. The pressure at which the mixture of hydraulic alumina and a solvent containing water is pressurized is more preferably 50 to 600 MPa, and even more preferably 200 to 600 MPa.

Next, we will explain another method for producing the composite member 1 in which the inorganic substance contained in the inorganic layer 10 is boehmite. The composite member 1 in which the inorganic substance is boehmite can be produced by mixing aluminum nitride powder with a solvent containing water, and then applying pressure and heating.

Specifically, first, aluminum nitride powder and a water-containing solvent are mixed to prepare a mixture. The water-containing solvent is preferably pure water or ion-exchanged water. The water-containing solvent may contain an acidic substance or an alkaline substance in addition to water. The water-containing solvent may contain water as the main component, and may contain, for example, an organic solvent (e.g., alcohol). Furthermore, the water-containing solvent may contain ammonia.

The amount of solvent added to aluminum nitride is preferably an amount that allows the hydrolysis reaction of aluminum nitride described below to proceed and produces aluminum hydroxide on the surface of the aluminum nitride. The amount of solvent added is preferably 5 to 100% by mass, more preferably 20 to 80% by mass, relative to the aluminum nitride.

Next, a resin layer containing resin and inorganic particles is placed inside the mold. Then, the mixture of aluminum nitride and a solvent containing water is filled inside the mold so that the mixture is placed on the surface of the resin layer. After the mixture is filled into the mold, the mold is heated as necessary. Then, pressure is applied to the resin layer and the mixture placed inside the mold, and the inside of the mold is put into a high-pressure state. At this time, aluminum nitride is highly packed, and the aluminum nitride particles are bonded to each other, resulting in high density. Specifically, by applying pressure while heating the mixture, aluminum nitride reacts with moisture to generate aluminum hydroxide on the surface of the aluminum nitride. The generated aluminum hydroxide diffuses between adjacent aluminum nitrides, gradually connecting the aluminum nitrides to each other. Then, a dehydration reaction proceeds due to heating, and the crystal structure changes from aluminum hydroxide to boehmite. As a result, adjacent aluminum nitride particles are bonded via the boehmite phase containing boehmite. In addition, by applying pressure while heating the mixture and the resin layer, inorganic substances derived from the mixture are directly fixed to the inorganic particles of the resin layer.

Then, by removing the molded body from inside the mold, a composite material 1 having an inorganic layer 10 and a resin layer 20 can be obtained.

The heating and pressurizing conditions for the mixture of aluminum nitride and a solvent containing water are not particularly limited as long as the reaction between aluminum nitride and the solvent and the dehydration reaction of aluminum hydroxide proceed. For example, it is preferable to heat the mixture to 50 to 300°C and pressurize it at a pressure of 10 to 600 MPa. When the resin contained in the resin layer is a thermoplastic resin, it is preferable to heat it at a temperature below the melting point of the thermoplastic resin. The temperature at which the mixture is heated is more preferably 80 to 250°C, and even more preferably 100 to 200°C. The pressure at which the mixture is pressurized is more preferably 50 to 600 MPa, and even more preferably 200 to 600 MPa.

Next, a method for manufacturing the composite member 1 in which the inorganic substance contained in the inorganic layer 10 is a metal oxide will be described. A solvent is added to the powder of the inorganic substance. The solvent is not particularly limited, but for example, a solvent capable of dissolving a part of the inorganic substance when the powder of the inorganic substance is pressurized and heated can be used. In addition, a solvent capable of reacting with the inorganic substance to produce an inorganic substance different from the inorganic substance can be used. As such a solvent, at least one selected from the group consisting of an acidic aqueous solution, an alkaline aqueous solution, water, an alcohol, a ketone, and an ester can be used. As the acidic aqueous solution, an aqueous solution having a pH of 1 to 3 can be used. As the alkaline aqueous solution, an aqueous solution having a pH of 10 to 14 can be used. As the acidic aqueous solution, an aqueous solution of an organic acid is preferably used. As the alcohol, an alcohol having 1 to 12 carbon atoms is preferably used.

Next, a resin layer containing a resin and inorganic particles is placed inside the mold. The mixture containing the inorganic substance and the solvent is then filled into the mold so that the mixture is placed on the surface of the resin layer. After the mixture is filled into the mold, the mold may be heated as necessary. Then, pressure is applied to the resin layer and mixture placed inside the mold, creating a high-pressure state inside the mold. At this time, the inorganic substance in the mixture is densified, and at the same time, the particles of the inorganic substance are bonded to each other. In addition, by applying pressure to the mixture and the resin layer while heating them, the inorganic substance derived from the mixture is directly fixed to the inorganic particles of the resin layer.

Here, when a solvent that dissolves part of the inorganic substance is used, the inorganic compound contained in the inorganic substance dissolves in the solvent under high pressure. The dissolved inorganic compound penetrates into the gaps between the inorganic substances. Then, by removing the solvent in the mixture in this state, bonds 12 derived from the inorganic substance are formed between the inorganic substances. Also, when a solvent that reacts with the inorganic substance to produce an inorganic substance different from the inorganic substance is used, the inorganic compound that constitutes the inorganic substance reacts with the solvent under high pressure. Then, the other inorganic substance produced by the reaction fills the gaps between the inorganic substances, and bonds 12 derived from the other inorganic substance are formed.

The heating and pressurizing conditions of the mixture containing the inorganic substance and the solvent are not particularly limited as long as the conditions are such that the dissolution of the surface of the inorganic substance proceeds when a solvent that dissolves a part of the inorganic substance is used as the solvent. In addition, the heating and pressurizing conditions of the mixture are not particularly limited as long as the reaction between the inorganic substance and the solvent proceeds when a solvent that reacts with the inorganic substance to produce an inorganic substance different from the inorganic substance is used as the solvent. For example, it is preferable to heat the mixture containing the inorganic substance and the solvent to 50 to 300°C and then pressurize it at a pressure of 10 to 600 MPa. The temperature at which the mixture containing the inorganic substance and the solvent is heated is more preferably 80 to 250°C, and even more preferably 100 to 200°C. When the resin contained in the resin layer is a thermoplastic resin, it is preferable to heat it at a temperature equal to or lower than the melting point of the thermoplastic resin. In addition, the pressure at which the mixture containing the inorganic substance and the solvent is pressurized is more preferably 50 to 400 MPa, and even more preferably 50 to 200 MPa.

Then, by removing the molded body from inside the mold, a composite material 1 having an inorganic layer 10 and a resin layer 20 can be obtained.

Here, a sintering method is known as a method for manufacturing an inorganic member containing ceramics. The sintering method is a method for obtaining a sintered body by heating an aggregate of solid powder containing an inorganic substance at a temperature lower than the melting point. However, in the sintering method, the solid powder is heated to, for example, 1000°C or higher. Therefore, even if an inorganic layer 10 containing an organic substance with low heat resistance is obtained using the sintering method, the organic substance will be carbonized by heating at a high temperature. However, in the manufacturing method of the composite member 1 of this embodiment, the organic substance is less likely to be carbonized because heating is performed at a low temperature of 300°C or less.

Furthermore, in the manufacturing method of this embodiment, the powder of the inorganic substance is pressurized while being heated, so that the inorganic substance aggregates to form a dense inorganic layer 10. As a result, the number of pores inside the inorganic layer 10 is reduced, and a composite member 1 having high strength can be obtained.

Thus, the manufacturing method of the composite member 1 according to this embodiment includes a step of mixing hydraulic alumina with a solvent containing water to obtain a mixture, and a step of pressurizing and heating the resin layer and the mixture while the mixture is placed on the surface of the resin layer. The heating and pressurizing conditions for the mixture are preferably a temperature of 50 to 300°C and a pressure of 10 to 600 MPa. In this manufacturing method, the composite member 1 is formed under low-temperature conditions, so that the inorganic layer 10 obtained is mainly composed of the boehmite phase. Therefore, a composite member 1 that is lightweight and has excellent chemical stability can be obtained in a simple manner.

In addition, a manufacturing method of a composite member 1 according to another embodiment includes a step of mixing aluminum nitride particles with a solvent containing water to obtain a mixture, and a step of pressurizing and heating the resin layer and the mixture while the mixture is placed on the surface of a resin layer. The heating and pressurizing conditions of the mixture are preferably a temperature of 50 to 300°C and a pressure of 10 to 600 MPa. Since the heating temperature in the manufacturing method of this embodiment is low, the aluminum nitride is bonded via the boehmite phase in the resulting inorganic layer 10. This makes it possible to obtain a composite member 1 with excellent mechanical strength and chemical stability in a simple manner.

In addition, a manufacturing method of a composite material 1 according to another embodiment includes a step of mixing a solvent that dissolves an inorganic substance or a solvent that reacts with an inorganic substance with a powder of the inorganic substance to obtain a mixture. The method also includes a step of pressurizing and heating the resin layer and the mixture while the mixture is placed on the surface of the resin layer. The heating and pressurizing conditions for the mixture are preferably a temperature of 50 to 300°C and a pressure of 10 to 600 MPa. In the manufacturing method of this embodiment, the composite material 1 is molded under such low-temperature conditions, so that changes in physical or chemical properties due to heat can be suppressed. As a result, a composite material 1 that can be used for a variety of applications can be obtained.

[Member with composite material]
Next, a member including the composite member 1 will be described. As described above, the composite member 1 can be formed into a thick plate, and is dense and therefore has excellent stability. In addition, the composite member 1 has high mechanical strength, and can be cut in the same way as general ceramic members, and can also be surface-treated. Therefore, the composite member 1 can be suitably used as a building member. There are no particular limitations on the building member, but examples of the building member include exterior wall materials (siding) and roofing materials. Other examples of the building member include road materials and exterior ditch materials.

The composite member 1 can also be suitably used as a component for electronic devices. Examples of components for electronic devices include structural materials, heat-resistant components, insulating components, heat dissipation components, heat insulating components, sealing materials, circuit boards, and optical components.

The present embodiment will be explained in more detail below with reference to examples, but the present embodiment is not limited to these examples.

Example 1
First, hydraulic alumina BK-112 manufactured by Sumitomo Chemical Co., Ltd. was prepared as an inorganic substance. The hydraulic alumina had a median particle size of 16 μm. The hydraulic alumina was a mixture of boehmite and gibbsite (aluminum hydroxide). The hydraulic alumina also contained ρ-alumina. Then, ion-exchanged water was weighed out so that the amount of the hydraulic alumina was 80 mass %, and then the hydraulic alumina and the ion-exchanged water were mixed using an agate mortar and pestle to obtain a mixture.

A 2 mm thick resin plate containing resin and inorganic particles was also prepared. The inorganic particles were mixed into the resin so that the amount of the inorganic particles was 33 parts by mass relative to the resin plate. For the resin plate, thermoplastic acrylic resin was used as the resin, and hydraulic alumina BK-112 manufactured by Sumitomo Chemical Co., Ltd. was used as the inorganic particles. The thermoplastic acrylic resin was made by mixing 75% by mass of MMA manufactured by Mitsubishi Gas Chemical Co., Ltd. and 25 wt% of PMMA manufactured by Asahi Chemical Industry Co., Ltd., and adding 0.3% by mass of Trigonox 121-50E manufactured by Kayaku Akzo Co., Ltd. as a polymerization initiator to heat cure the resin. The heat curing conditions were 1.5 hours at 70°C, 0.5 hours at 80°C, and 1 hour at 120°C, in that order.

Next, a resin plate was placed inside a cylindrical molding die (Φ10) having an internal space. The mixture obtained as described above was filled into the inside of the die so that the mixture was placed on the surface of the resin plate. The resin plate and mixture placed inside the die were then heated and pressurized under conditions of 400 MPa, 80°C, and 10 minutes to obtain a composite member having an inorganic layer and a resin layer as a test sample.

Example 2
A composite member was obtained as a test sample in the same manner as in Example 1, except that the inorganic particles used in the resin plate were changed to silica particles (fused silica F207C manufactured by Fumitec Co., Ltd.).

(Comparative Example 1)
A composite member was obtained as a test sample in the same manner as in Example 1, except that no inorganic particles were kneaded into the resin plate.

[evaluation]
(Scotch tape test)
The resin layer of the cylindrical test sample was fixed, and a tape (product number No. 29) made by Nitto Denko Corporation was attached to the surface of the inorganic layer while taking care not to trap air bubbles. The tape was then vigorously peeled off from the inorganic layer to evaluate the adhesion between the inorganic layer and the resin layer. The results of the Scotch tape test are shown in Table 1.

As shown in Table 1, the results of the Scotch tape test showed that the inorganic layer and the resin layer did not peel off in the test samples of Examples 1 and 2, but peeling occurred in the test sample of Comparative Example 1. These results show that the addition of inorganic particles to the resin layer improves the adhesion between the inorganic layer and the resin layer.

(Cross-section observation)
The cross section of the cylindrical test sample was observed using a scanning electron microscope (SEM). Gold sputtering was applied to the observation surface. FIG. 5 is an SEM image of the test sample of Example 1 observed at 500x. FIG. 6 is an SEM image of the test sample of Example 1 observed at 5000x. FIG. 7 is an SEM image of the test sample of Example 2 observed at 500x. FIG. 8 is an SEM image of the test sample of Example 2 observed at 5000x. FIG. 9 is an SEM image of the test sample of Comparative Example 1 observed at 500x. FIG. 10 is an SEM image of the test sample of Comparative Example 1 observed at 5000x.

In the SEM image of Example 1, as shown in the frame in Figure 6, the inorganic particles 22 contained in the resin layer 20 and the particles 11 contained in the inorganic layer 10 were continuously and integrally bonded to each other. In the SEM image of Example 2, as shown in the frame in Figure 8, the inorganic particles 22 contained in the resin layer 20 and the particles 11 contained in the inorganic layer 10 were not continuously and integrally bonded to each other, but were directly fixed to each other. In the SEM image of Comparative Example 1, as shown in the frame in Figure 10, voids were observed between the resin layer 20 and the inorganic layer 10.

From the results of the Scotch tape test and cross-sectional observation, it is believed that when the resin layer 20 contains inorganic particles 22, the inorganic particles 22 are directly adhered to the inorganic substance contained in the inorganic layer 10, thereby improving the adhesion between the resin layer 20 and the inorganic layer 10.

(Porosity measurement)
First, a cross-section polisher process (CP process) was performed on the cylindrical cross section of the test sample of Example 1. Next, a scanning electron microscope (SEM) was used to observe a backscattered electron image of the cross section of the test sample of Example 1 at a magnification of 2000 times. The backscattered electron images obtained by observing three positions (positions 1 to 3) on the cross section of the test sample of Example 1 are shown in Figs. 11, 13, and 15, respectively.

Next, the SEM images of the three fields of view were binarized to clarify the pores. The binarized images of the backscattered electron images of Figures 11, 13, and 15 are shown in Figures 12, 14, and 16, respectively. In Figures 12, 14, and 16, the black parts are pores. The area ratio of the pores was calculated from the binarized images, and the average value was taken as the porosity. From Figure 12, the area ratio of the pores at position 1 was 0.69%. From Figure 14, the area ratio of the pores at position 2 was 0.75%. From Figure 16, the area ratio of the pores at position 3 was 1.14%. Therefore, the porosity of the test sample of Example 1 was 0.86%, which is the average value of the area ratios of the pores at positions 1 to 3.

The porosity measurement results showed that the porosity of the inorganic layer in Example 1 was small. It is believed that the small porosity of the inorganic layer prevents cracks from occurring in the inorganic layer starting from the pores. Note that while only the porosity of the inorganic layer in Example 1 was evaluated, the inorganic layer in Example 2 was also produced using the same materials and method, and so similar results are expected.

(FT-IR (Fourier transform infrared spectroscopy))
The infrared absorption spectrum of the inorganic layer of Example 1 was measured using an IR Tracer-100 manufactured by Shimadzu Corporation. As a negative control, powder of high-purity alumina AA-3 manufactured by Sumitomo Chemical Co., Ltd. was also measured in the same manner. As a positive control, aluminum hydroxide KH-108 manufactured by KC Corporation was also measured in the same manner. The infrared absorption spectrum was measured in a transmission mode, in a measurement region of 400 to 7500 cm ^-1 (1.33 to 25 μm), and with an accumulation count of 30. FIG. 17 shows the infrared absorption spectra of the inorganic layer, alumina, and aluminum hydroxide of Example 1.

Next, the peak area of the peak derived from the hydroxyl group was calculated from the obtained infrared absorption spectrum. Specifically, the peak area was calculated according to the following formula (1).

In the above formula (1), S1 is the peak area (cm ^-1 ), v ₁ is the wave number 2600 cm ^-1 , and v ₂ is the wave number 3800 cm ^-1 , A(v) is the absorbance at wave number v, BG(v) is the absorbance of the BG (background) line at wave number v, and Δv is the wave number resolution (cm ^-1 ). Note that the new tilde in the above formula (1) is written as v in the text. The BG line is a straight line connecting the infrared absorption spectra of the background region at both bases of the peak. The background region is the wave number region of 2400 cm ^-1 or more and less than 2600 cm ^-1 , and the wave number region of more than 3800 cm ^-1 and 4000 cm ^-1 or less. Table 2 shows the peak area of each infrared absorption spectrum.

17 and the results in Table 2, compared with alumina, whose peak area is at the background level, the peak area of the inorganic layer of Example 1 is 3.76 cm ^-1 , and a peak derived from a hydroxy group was detected in the inorganic layer of Example 1. Note that, although only the peak area of the inorganic layer of Example 1 was calculated, the inorganic layer of Example 2 was also produced from the same material and by the same method, and therefore similar results are expected.

(X-ray diffraction measurement)
The XRD pattern of the powder obtained by pulverizing the inorganic layer of Example 1 in an alumina mortar was measured using a MiniFlex powder XRD device manufactured by Rigaku Corporation. The X-ray source was CuKα (wavelength λ=1.54056 Å), the tube voltage was 40 kV, the tube current was 15 mA, and the measurement range was 2θ=10° to 70°. As a negative control, the XRD pattern of powder of high-purity alumina AA-3 manufactured by Sumitomo Chemical Co., Ltd. was also measured in the same manner. FIG. 18 is a graph showing the XRD pattern of the inorganic layer of Example 1 and the XRD pattern of alumina. FIG. 19 is a graph showing an enlarged view of the XRD pattern of FIG. 18.

Next, the peak area of the peak centered on the main peak (2θ = 14.4°) of boehmite (AlOOH) was calculated from the obtained XRD pattern. Specifically, the peak area was calculated according to the following formula (2).

In the above formula (2), S2 represents the peak area (cm ^-1 ), 2θ ₁ represents the angle 2θ = 12°, and 2θ ₂ represents the angle 2θ = 16.8°. I (2θ) represents the intensity (cps) at the angle 2θ, BG (2θ) represents the intensity (cps) of the BG (background) line at the angle 2θ, and Δ (2θ) represents the step angle (2θ = 0.02°). The BG line was a straight line connecting the XRD patterns of the background regions at both ends of the peak. The background region was an angle region of 11.5° or more and less than 12°, and an angle region of more than 16.8° and 17.3° or less. Table 3 shows the peak area of each XRD pattern.

From the results in Figures 18 and 19 and Table 3, compared to alumina, which has a peak area at the background level, the peak area of the inorganic layer of Example 1 was 8640° (2θ)·cps, and a peak derived from hydroxyl groups was detected in the inorganic layer of Example 1.

Next, the obtained XRD pattern was subjected to Rietveld analysis to determine the proportion of each phase. Figure 20 is a graph showing, from the top, the fitting results of the XRD pattern of Example 1, and the XRD patterns of boehmite, gamma alumina, and alpha alumina registered in the ICSD (Inorganic Crystal Structure Database). Figure 21 is a graph showing, from the top, the fitting results of the XRD pattern of alumina, and the XRD patterns of alpha alumina and boehmite registered in the ICSD. Table 4 shows the proportions of each phase obtained by Rietveld analysis.

As a result of Rietveld analysis, compared to alumina, in which the proportion of boehmite phase is at the background level, the inorganic layer of Example 1 had a boehmite phase of 56 mass%, and a peak derived from a hydroxyl group was detected in the inorganic layer of Example 1. Note that while only the inorganic layer of Example 1 was analyzed, the inorganic layer of Example 2 was also produced using the same materials and method, and therefore similar results are expected.

(TG (thermogravimetry))
Fig. 22 shows TG curves of boehmite and aluminum hydroxide. As shown in Fig. 22, when boehmite or aluminum hydroxide is heated, weight loss is observed due to the elimination of hydroxyl groups by dehydration condensation to generate alumina. From this result, when inorganic substances having hydroxyl groups such as boehmite or aluminum hydroxide are heated as solid powder to, for example, 1000°C or higher as in the sintering method, alumina is generated. Therefore, it is considered that hydroxyl groups as in this embodiment are not detected in such sintered bodies.

The entire contents of Patent Application No. 2020-125102 (filing date: July 22, 2020) are incorporated herein by reference.

Although the present embodiment has been described above, the present embodiment is not limited to this, and various modifications are possible within the scope of the gist of the present embodiment.

According to the present disclosure, it is possible to provide a composite component in which an inorganic layer and a resin layer are firmly bonded without the use of an adhesive.

Reference Signs List 1 Composite member 10 Inorganic layer 20 Resin layer 21 Resin 22 Inorganic particles

Claims (7)

an inorganic layer including an inorganic material containing at least one of a metal oxide and a metal oxide hydroxide;
a resin layer provided on a surface of the inorganic layer, the resin layer containing a resin and inorganic particles dispersed in the resin and directly bonded to the inorganic substance of the inorganic layer;
Equipped with
The inorganic layer has a cross-sectional porosity of 20% or less,
A composite member, wherein a peak derived from a hydroxy group is detected from the inorganic layer when the composite member is measured by infrared spectroscopy or X-ray diffraction method. The composite member according to claim 1, wherein the porosity in the cross section of the inorganic layer is 10% or less. The composite member according to claim 1 or 2, wherein the inorganic particles have hydroxyl groups. A composite member according to any one of claims 1 to 3, wherein the inorganic particles and the inorganic substance contained in the inorganic layer are continuously and integrally bonded. A composite member according to any one of claims 1 to 4, wherein the inorganic particles contain a metal element contained in the inorganic material of the inorganic layer. A composite member according to any one of claims 1 to 5, wherein the content of the inorganic particles in the resin layer is 10% by volume or more and 70% by volume or less. A composite member according to any one of claims 1 to 6, wherein the inorganic material contained in the inorganic layer is polycrystalline.

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